The present invention relates generally to the field of emergency lighting. More specifically, the present invention relates to emergency lighting used to indicate a path leading to an exit for the evacuation of a passenger vehicle or building (e.g., following an accident or outbreak of a fire).
The invention has particular application to passenger vehicles and/or buildings that include rows of seats provided on either side of an aisle with an exit at one or both ends of the aisle. Exits may also be provided on one or both sides of the aisle between the ends. Passenger vehicles of this type may include aircraft, trains, buses, coaches, ships, and other passenger vehicles having seats located adjacent to an aisle leading to an exit.
One example of a previous emergency lighting system is described in United Kingdom Patent No. 2,314,536. In the described system, a pathway to an exit is illuminated by photoluminescent material extending along the aisle for passengers to follow to the exit. When exposed to a light source, the photoluminescent material is activated and provides a low level light source that is normally invisible in daylight but is visible under conditions of darkness or low illumination from other light sources. For example, the photoluminescent material may be visible in the event that smoke from a fire blocks the overhead lights that normally illuminate the passenger cabin.
The level of illumination provided by the photoluminescent material under these conditions is sufficient to guide passengers to an exit to evacuate the aircraft and avoids the problems associated with electrically powered systems. For example, electrically powered systems may be prone to failure at the time they are required due to damage to the wiring supplying power to the system.
The pathway to the exit may include photoluminescent guides of predetermined length (e.g., one meter, two meters, etc.). The photoluminescent guides may be laid end to end along the aisle to provide a substantially continuous path of light when illuminated. Employing guides of pre-determined length facilitates manufacture, storage, transportation, handling and installation of the guides.
In some implementations, the pathway has a length that is not a multiple of the predetermined guide lengths. When the pathway has a length that is not an integer multiple of the predetermined guide lengths, it may be necessary to shorten one or more of the guides during installation. Shortening the guide may include cutting the guide. If the guide is sealed to prevent ingress of liquids and dirt, shortening the guide may also include re-sealing the cut end of the guide.
The photoluminescent material may be provided by an insert received within a housing of light transmitting material. One example of a photoluminescent material is strontium aluminate, which may include a dopant to enhance the photoluminescent properties. Strontium aluminate has a pale yellow color. A colored film of sheet plastics can be placed above the insert in the housing to adapt the color of the guide to match the surroundings.
In some implementations, the film of sheet plastics is separate from the insert. Providing the film of sheet plastics and the insert as separate components can lead to problems when a guide is cut to length. For example, the film of sheet plastics may be wrapped around the ends of the fixed length insert during manufacture to prevent the film from wrinkling and adversely affecting the visual appearance of the guide. When a section of guide is cut to length, the film of sheet plastics can no longer be wrapped around the cut end of the insert. As a result, the film may become wrinkled and/or not cover the entire length of the insert.
The present invention seeks to address the aforementioned problems and to provide further improvements to photoluminescent emergency lighting systems. In particular, the present invention seeks to provide improved photoluminescent emergency lighting systems for passenger vehicles such as aircraft.
One desired aim of the present invention is to provide a photoluminescent guide for an emergency lighting system, as well as an emergency lighting system employing the guide, that overcomes or mitigates one or more of the aforementioned problems and disadvantages.
Another desired aim of the present invention is to provide a photoluminescent insert for an emergency lighting system as well as a photoluminescent lighting system employing the insert.
Yet another desired aim of the present invention is to provide a method for installing an emergency lighting system employing the photoluminescent guide and/or photoluminescent insert.